9. Black Widow (Marvel)
Who is this? A former soviet spy, Nastasha Romanoff defected to the US and is now a high ranking super spy in the secret organization SHIELD, where she answers directly to SHIELD head Nick Fury and is a part-time member of the Avengers.
Why is this person a better choice than WW? Black Widow could easily be the first female to carry a superhero movie since Hally Berry's "Catwoman." She's a character who has already been established over 3 movies in the Marvel Cinematic Universe: introduced in Iron Man 2, her character was expanded upon in the Avengers, and she is one of the lead characters in Marvel's latest, Captain America: The Winter Soldier. A fan favorite in each of those movies, Black Widow is a character that already has a lot of traction with both hardcore comic fans and the casual audience and is ready to break out into her own film franchise.
Who should be cast? Scarlett Johanssen has the role now and there is certainly no need to recast. Scarlett is a big name in Hollywood, and her proven status as a box office draw is a big reason why this movie could actually happen. She's sexy, intelligent, funny, and generally a great actress, who could easily carry the weight of a movie of this magnitude.